Blogs

About this blog

I'm a well-known mainframe performance guy, with almost 30 years of experience helping customers manage systems. I also dabble in lots of other technology. I've sought to widen the Performance role, incorporating aspects of infrastructural architecture.
I'm a world-famous podcaster and screencaster (albeit VERY thinly spread). :-)

Tags

It's been an awfully long time since I wrote When Good Work Doesn't Go To zIIP / zAAP Heaven . And too long since I posted anything at all. In fact I had a bunch of posts in my brain until this morning when a customer asked me a question which turned into this blog post. (Those posts are still in my brain and will probably see the light of day eventually, including one based on a customer... [More]

I can't believe it's been almost a week since I wrote Batch Capacity Planning, Part 1 - CPU . Where did the time go? Re-reading it I'm struck by the overwhelming theme of Batch's unpredictability and lumpiness. This is true of memory, as well, but to a much lesser degree. Why to a lesser degree? Well, in most systems I look at the memory usage is mostly fairly constant and dominated by big... [More]

I was going to start this post with an apology. But, as any sensible blogger would, I left it a few days to write this. Now I realise that there's a wider point than the "I was wrong" one. (But I was wrong - in a way that I think many other people might've been wrong too.) So let me talk about two things in this post: zAAP and zIIP Delay. How I came to be wrong and what we can all... [More]

This is the post I was going to write before the discussion that led to CICS VSAM Buffering arose. It's about getting more insight into how WLM is set up and performing than RMF Workload Activity Report data alone allows. I recognise some of this can be done with the WLM policy in hand. But this is about an SMF-based approach. (The piece you can't do with SMF is discerning the WLM classification... [More]

I was lucky enough to be in Silicon Valley Lab for DB2 BootCamp last week. There I ran into a DB2 developer I've worked very successfully with in the past - John Tobler. (He's the guy I look to for questions and issues with DB2 SMF data.) We had a good discussion about something I'd personally like to see in DB2 Accounting Trace - more WLM information - and this post is as a result of this... [More]

You'd think it would be pretty simple to draw a line. Right? This post discusses an enhancement I'd like to make to my current reporting - and I'm pretty sure that technically I can do it. The question is whether I should . Consider my current "Memory by address space within Service Class" graph. Here's a sample: And here's what I think I might like it to look like: Obviously the line's... [More]

It’s possible I’ve written something about this before:
My blog is so extensive now it’s hard to find out exactly what I’ve written about (and I’m going to have to do something about that). I say “written something ” because I know for sure I haven’t written about the SMF record field I want to introduce you to now. Previously If when you send me... [More]